View source for 3uj4


==Crystal structure of the apo-inositol 1,4,5-trisphosphate receptor==
<StructureSection load='3uj4' size='340' side='right' caption='[[3uj4]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3uj4]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Buffalo_rat Buffalo rat]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3UJ4 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3UJ4 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3uj0|3uj0]]</td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">Itpr1, Insp3r ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10116 Buffalo rat])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3uj4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3uj4 OCA], [http://pdbe.org/3uj4 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3uj4 RCSB], [http://www.ebi.ac.uk/pdbsum/3uj4 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3uj4 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/ITPR1_RAT ITPR1_RAT]] Intracellular channel that mediates calcium release from the endoplasmic reticulum following stimulation by inositol 1,4,5-trisphosphate. Plays a role in ER stress-induced apoptosis. Cytoplasmic calcium released from the ER triggers apoptosis by the activation of CaM kinase II, eventually leading to the activation of downstream apoptosis pathways (By similarity). 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Inositol-1,4,5-trisphosphate receptors (InsP(3)Rs) and ryanodine receptors (RyRs) are tetrameric intracellular Ca(2+) channels. In each of these receptor families, the pore, which is formed by carboxy-terminal transmembrane domains, is regulated by signals that are detected by large cytosolic structures. InsP(3)R gating is initiated by InsP(3) binding to the InsP(3)-binding core (IBC, residues 224-604 of InsP(3)R1) and it requires the suppressor domain (SD, residues 1-223 of InsP(3)R1). Here we present structures of the amino-terminal region (NT, residues 1-604) of rat InsP(3)R1 with (3.6 A) and without (3.0 A) InsP(3) bound. The arrangement of the three NT domains, SD, IBC-beta and IBC-alpha, identifies two discrete interfaces (alpha and beta) between the IBC and SD. Similar interfaces occur between equivalent domains (A, B and C) in RyR1 (ref. 9). The orientations of the three domains when docked into a tetrameric structure of InsP(3)R and of the ABC domains docked into RyR are remarkably similar. The importance of the alpha-interface for activation of InsP(3)R and RyR is confirmed by mutagenesis and, for RyR, by disease-causing mutations. Binding of InsP(3) causes partial closure of the clam-like IBC, disrupting the beta-interface and pulling the SD towards the IBC. This reorients an exposed SD loop ('hotspot' (HS) loop) that is essential for InsP(3)R activation. The loop is conserved in RyR and includes mutations that are associated with malignant hyperthermia and central core disease. The HS loop interacts with an adjacent NT, suggesting that activation re-arranges inter-subunit interactions. The A domain of RyR functionally replaced the SD in full-length InsP(3)R, and an InsP(3)R in which its C-terminal transmembrane region was replaced by that from RyR1 was gated by InsP(3) and blocked by ryanodine. Activation mechanisms are conserved between InsP(3)R and RyR. Allosteric modulation of two similar domain interfaces within an N-terminal subunit reorients the first domain (SD or A domain), allowing it, through interactions of the second domain of an adjacent subunit (IBC-beta or B domain), to gate the pore.

Structural and functional conservation of key domains in InsP(3) and ryanodine receptors.,Seo MD, Velamakanni S, Ishiyama N, Stathopulos PB, Rossi AM, Khan SA, Dale P, Li C, Ames JB, Ikura M, Taylor CW Nature. 2012 Jan 29. doi: 10.1038/nature10751. PMID:22286060<ref>PMID:22286060</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3uj4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Inositol 1%2C4%2C5-Trisphosphate Receptor|Inositol 1%2C4%2C5-Trisphosphate Receptor]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Buffalo rat]]
[[Category: Ikura, M]]
[[Category: Ishiyama, N]]
[[Category: Seo, M D]]
[[Category: Stathopulos, P]]
[[Category: 5-trisphosphate]]
[[Category: Apo-state]]
[[Category: Inositol 1]]
[[Category: Ip3-binding core domain]]
[[Category: Signaling protein]]
[[Category: Suppressor domain]]